Methods and apparatuses for making and using planarizing pads for mechanical and chemical-mechanical planarization of microelectronic substrates

ABSTRACT

Methods and apparatuses for planarizing a microelectronic substrate. In one embodiment, a planarizing pad for mechanical or chemical-mechanical planarization includes a base section and a plurality of embedded sections. The base section has a planarizing surface, and the base section is composed of a first material. The embedded sections are arranged in a desired pattern of voids, and each embedded section has a top surface below the planarizing surface to define a plurality of voids in the base section. The embedded sections are composed of a second material that is selectively removable from the first material. A planarizing pad in accordance with an embodiment of the invention can be made by constructing the embedded sections in the base section and then removing a portion of the embedded sections from the base section. By removing only a portion of the embedded sections, this procedure creates the plurality of voids in the base section and leaves the remaining portions of the embedded sections. After the pad is used to planarize one or more substrate assemblies and the voids are filled with waste matter or otherwise altered, an etchant can be deposited on the pad to subsequently remove an incremental depth of the embedded sections faster than the base section to reform the voids over the embedded sections.

TECHNICAL FIELD

[0001] This invention relates to planarizing pads in mechanical and/orchemical-mechanical planarization of microelectronic substrates.

BACKGROUND

[0002] Mechanical and chemical-mechanical planarization processes(collectively “CMP”) are used in the manufacturing of electronic devicesfor forming a flat surface on semiconductor wafers, field emissiondisplays and many other microelectronic device substrate assemblies. CMPprocesses generally remove material from a substrate assembly to createa highly planar surface at a precise elevation in the layers of materialon the substrate assembly. FIG. 1 schematically illustrates an existingweb-format planarizing machine 10 for planarizing a substrate 12. Theplanarizing machine 10 has a support table 14 with a top-panel 16 at aworkstation where an operative portion (A) of a planarizing pad 40 ispositioned. The top-panel 16 is generally a rigid plate to provide aflat, solid surface to which a particular section of the planarizing pad40 may be secured during planarization.

[0003] The planarizing machine 10 also has a plurality of rollers toguide, position and hold the planarizing pad 40 over the top-panel 16.The rollers include a supply roller 20, idler rollers 21, guide rollers22, and a take-up roller 23. The supply roller 20 carries an unused orpre-operative portion of the planarizing pad 40, and the take-up roller23 carries a used or post-operative portion of the planarizing pad 40.Additionally, the left idler roller 21 and the upper guide roller 22stretch the planarizing pad 40 over the top-panel 16 to hold theplanarizing pad 40 stationary during operation. A motor (not shown)generally drives the take-up roller 23 to sequentially advance theplanarizing pad 40 across the top-panel 16, and the motor can also drivethe supply roller 20. Accordingly, clean pre-operative sections of theplanarizing pad 40 may be quickly substituted for used sections toprovide a consistent surface for planarizing and/or cleaning thesubstrate 12.

[0004] The web-format planarizing machine 10 also has a carrier assembly30 that controls and protects the substrate 12 during planarization. Thecarrier assembly 30 generally has a substrate holder 32 to pick up, holdand release the substrate 12 at appropriate stages of the planarizingprocess. Several nozzles 33 attached to the substrate holder 32 dispensea planarizing solution 44 onto a planarizing surface 42 of theplanarizing pad 40. The carrier assembly 30 also generally has a supportgantry 34 carrying a drive assembly 35 that can translate along thegantry 34. The drive assembly 35 generally has an actuator 36, a driveshaft 37 coupled to the actuator 36, and an arm 38 projecting from thedrive shaft 37. The arm 38 carries the substrate holder 32 via aterminal shaft 39 such that the drive assembly 35 orbits the substrateholder 32 about an axis B-B (as indicated by arrow R₁). The terminalshaft 39 may also rotate the substrate holder 32 about its central axisC-C (as indicated by arrow R₂).

[0005] The planarizing pad 40 and the planarizing solution 44 define aplanarizing medium that mechanically and/or chemically-mechanicallyremoves material from the surface of the substrate 12. The planarizingpad 40 used in the web-format planarizing machine 10 is typically afixed-abrasive planarizing pad in which abrasive particles are fixedlybonded to a suspension material. In fixed-abrasive applications, theplanarizing solution is a “clean solution” without abrasive particlesbecause the abrasive particles are fixedly distributed across theplanarizing surface 42 of the planarizing pad 40. In other applications,the planarizing pad 40 may be a non-abrasive pad without abrasiveparticles that is composed of a polymeric material (e.g., polyurethane)or other suitable materials. The planarizing solutions 44 used with thenon-abrasive planarizing pads are typically CMP slurries with abrasiveparticles and chemicals to remove material from a substrate.

[0006] To planarize the substrate 12 with the planarizing machine 10,the carrier assembly 30 presses the substrate 12 against the planarizingsurface 42 of the planarizing pad 40 in the presence of the planarizingsolution 44. The drive assembly 35 then orbits the substrate holder 32about the axis B-B, and optionally rotates the substrate holder 32 aboutthe axis C-C, to translate the substrate 12 across the planarizingsurface 42. As a result, the abrasive particles and/or the chemicals inthe planarizing medium remove material from the surface of the substrate12.

[0007] The CMP processes should consistently and accurately produce auniformly planar surface on the substrate assembly to enable precisefabrication of circuits and photo-patterns. During the fabrication oftransistors, contacts, interconnects and other features, many substrateassemblies develop large “step heights” that create a highly topographicsurface across the substrate assembly. Such highly topographicalsurfaces can impair the accuracy of subsequent photolithographicprocedures and other processes that are necessary for forming sub-micronfeatures. For example, it is difficult to accurately focus photopatterns to within tolerances approaching 0.1 micron on topographicsubstrate surfaces because sub-micron photolithographic equipmentgenerally has a very limited depth of field. Thus, CMP processes areoften used to transform a topographical substrate surface into a highlyuniform, planar substrate surface at various stages of manufacturing themicroelectronic devices.

[0008] One problem with conventional CMP methods is that the planarizingsurface 42 of the planarizing pad 40 can wear unevenly or become glazedwith accumulations of slurry and/or material removed from the substrate12 or the planarizing pad 40. One conventional approach to address thisproblem is to condition the planarizing pad 40 by abrading theplanarizing surface 42 with an abrasive disk (not shown). In a typicalconditioning cycle, the abrasive disk removes accumulations of wastematter and also removes a layer of material from the pad 40. A drawbackwith this approach is that the equipment required for conditioning theplanarizing pad 40 adds complexity to the planarizing machine 10.Moreover, if the conditioning operation is performed separately from theplanarizing operation, it reduces the time that the planarizing pad 40is available for planarizing substrates. Conventional conditioningprocesses can thus limit the overall efficiency and throughput of theapparatus.

[0009] An additional drawback of methods that condition pads with aconditioning stone is that it is difficult to condition pads withgrooves or small voids without destroying the grooves. Conditioningstones, for example, may produce inconsistent distributions of grooveson the planarizing surface of a planarizing pad from one planarizingcycle to another. Conditioning stones may also change the depth or thewidth of existing grooves over the life of a planarizing pad.Conditioning planarizing pads with conditioning stones may thus producea non-uniform or inconsistent distribution of slurry under amicroelectronic device substrate assembly. Therefore, conditioningstones often cause planarizing pads to produce inconsistent polishingrates over the life of the pads.

[0010] One approach to address this drawback is to eliminate the need tocondition the pad by making the planarizing surface or the entireplanarizing pad disposable. For example, U.S. application Ser. No.09/001,333, which is herein incorporated by reference, discloses adisposable planarizing pad film made from materials such as Mylar orpolycarbonate. The pads disclosed in application Ser. No. 09/001,333 canhave microfeatures of different heights that entrap small volumes of anabrasive slurry and maintain the slurry in contact with the substrate.The microfeatures can be formed using a variety of techniques, such asembossing or photo-patterning. Although disposable pads have many goodapplications, they do not address the problems of conditioningnon-disposable pads with conditioning stones, and the disposable padsmay not be suitable for all CMP applications. Therefore, there is stilla need for developing planarizing pads and conditioning processes thatprovide consistent results over the life of non-disposable planarizingpads.

SUMMARY OF THE INVENTION

[0011] The present invention is directed toward planarizing pads forplanarizing microelectronic substrates, planarizing machines withplanarizing pads, methods for making planarizing pads, and methods forplanarizing the microelectronic substrates. In one embodiment, aplanarizing pad for mechanical or chemical-mechanical planarizationincludes a base section and a plurality of embedded sections. The basesection has a planarizing surface and it is composed of a firstmaterial. The embedded sections are arranged in a desired pattern ofvoids or grooves for holding a desired distribution of planarizingsolution under a substrate assembly. Each embedded section has a topsurface below the planarizing surface to define a void in the basesection. As such, the plurality of embedded sections define a pattern ofvoids in the base section. The embedded sections are composed of asecond material that is selectively removable from the first material.

[0012] One process for making a planarizing pad in accordance with anembodiment of the invention includes forming a pad body by constructingthe embedded sections in the base section. This embodiment for making aplanarizing pad can further include removing an incremental portion ofthe embedded sections from the base section without removing all of thematerial of the embedded sections. By removing only an incrementalportion of the embedded sections, this procedure creates the pluralityof voids in the base section and leaves the remaining portions of theembedded sections in the base section. After the pad is used toplanarize one or more substrate assemblies and the voids are filled withwaste matter or the planarizing surface wears down, an etchant can bedeposited on the pad to subsequently etch another incremental portion ofthe embedded sections faster than the base section to reform the voidsover the embedded sections. The planarizing pad can thus be chemicallyconditioned in manner that provides a consistent pattern and size ofvoids over the life of the planarizing pad.

[0013] In one particular embodiment for making a planarizing pad, thepad body initially comprises a photo-sensitive material that becomesmore soluble in a selected etchant upon exposure to a particularradiation (e.g., light). The procedure for constructing the embeddedsections in the base section can comprise irradiating portions of thebase section corresponding to the desired pattern of voids with theselected radiation. The unexposed portions of the pad body can definethe first material of the base section, and the exposed portions of thepad body can change into the second material to define the embeddedsections. The exposure time of the light is set to change the firstmaterial into the second material to the selected depth within the basesection. The embedded sections generally extend to depth that is greaterthan the desired depth of the voids to provide enough of the secondmaterial for incrementally reforming the voids over several conditioningcycles.

BRIEF DESCRIPTION OF DRAWINGS

[0014]FIG. 1 is a partial schematic side of elevational view of aplanarizing apparatus in accordance with the prior art.

[0015]FIG. 2 is a schematic side elevational view illustrating aplanarizing machine including a planarizing pad in accordance with oneembodiment of the invention.

[0016]FIG. 3 is a schematic side elevational view of a planarizing padat one stage of a conditioning cycle in accordance with one embodimentof a method of the invention.

[0017]FIG. 4 is a schematic side elevational view of the planarizing padat another stage of a conditioning cycle in accordance with anembodiment of a method of the invention.

[0018]FIG. 5 is a schematic side cross-sectional view of a method formanufacturing the planarizing pad in accordance with one embodiment ofthe invention.

[0019]FIG. 6 is a schematic side cross-sectional view of a method formanufacturing a planarizing pad in accordance with another embodiment ofthe invention.

[0020] FIGS. 7A-7D are partial schematic side cross-sectional views of amethod for manufacturing the planarizing pad in accordance with anotherembodiment of the invention.

[0021] FIGS. 8A-8E are schematic side elevational views illustrating aportion of a photo-polymer composite undergoing a photo-etching processin accordance with an embodiment of the invention.

[0022]FIG. 9 is a partial schematic side cross-sectional view of a stagein a method for manufacturing the planarizing pads illustrated in FIGS.7A-7D.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0023] The present disclosure describes planarizing pads, methods formaking planarizing pads, and methods for mechanical and/orchemical-mechanical planarization of semiconductor wafers, fieldemission displays and other types of microelectronic device substrateassemblies. The term “substrate assembly” includes both base substrateswithout microelectronic components and substrates having assemblies ofmicroelectronic components. Many specific details of certain embodimentsof the invention are set forth in the following description, and inFIGS. 2-9, to provide a thorough understanding of these embodiments. Oneskilled in the art, however, will understand that the present inventionmay have additional embodiments, or that the invention may be practicedwithout several of the details described below.

[0024]FIG. 2 is a cross-sectional view schematically illustrating aplanarizing machine 100 with a planarizing pad 140 in accordance withone embodiment of the invention. The planarizing machine 100 is a rotarymachine including a platen 120 attached to a drive assembly 126 thatrotates the platen 120 (arrow R₁) or translates the platen 120horizontally (not shown). The planarizing machine 100 also includes acarrier assembly 130 having a substrate holder 132, an arm 134 carryingthe substrate holder, and a drive assembly 136 coupled to the arm 134.The substrate holder 132 can include a plurality of nozzles 133 todispense a planarizing solution 139 onto the planarizing pad 140. Inoperation, the substrate holder 132 holds a substrate assembly 12, andthe drive assembly 136 moves the substrate assembly 12 by rotating(arrow R₂) and/or translating (arrow T) the substrate holder 132.

[0025] The planarizing pad 140 has a pad body 142 including a basesection 143 and a plurality of embedded sections 144 in the base section143. The base section 143 has a planarization surface defined by one ormore planarizing regions 146. The embedded sections 144 have topsurfaces 145 below planarizing regions 146 of the base section 143. Thedifference in height between the planarizing regions 146 and the topsurfaces 145 defines a plurality of voids 147 in the base section 143over the embedded sections 144. The planarizing regions 146 contact thesubstrate 12 during a planarizing cycle, and the voids 147 extend belowthe planarizing regions 146 to hold small volumes of the planarizingsolution 139 under the substrate 12. The voids 147 can be grooves,shallow wells or other structures that hold the planarizing solution 139under the substrate 12. The voids 147 are arranged in a desired voidpattern to provide a predetermined distribution of the planarizingsolution 139 under the substrate 12. As explained in more detail below,the embedded sections 144 are arranged in the desired pattern of thevoids to ensure that the void pattern is consistently maintained overthe life of the planarizing pad 140.

[0026] The base section 143 comprises a first material and the embeddedsections 144 comprise a second material. The first and second materialshave at least one different physical property and/or chemical propertythat makes the second material selectively removable from the firstmaterial. As used herein, the term “selectively removable” generallymeans that a selected solution dissolves or otherwise removes the secondmaterial of the embedded sections 144 faster than the first material ofthe base section 143. The first and second materials can initially bethe same compound or two different compounds. When the first and secondmaterials are initially the same compound, the compound is treated sothat a property of the substance is changed in the base section 143and/or the embedded sections 144 to either make the base section 143less soluble or the embedded sections 144 more soluble in the selectedsolution. The pad body 142, for example, can be composed of aphoto-sensitive material that is exposed to a selected radiation tochange the property of the photo-sensitive material in either the basesection 143 or the embedded sections 144. When the first and secondmaterials are different compounds, the base section 143 is composed of afirst compound and the embedded sections 144 are composed of a secondcompound that is more soluble in the selected solution.

[0027]FIGS. 3 and 4 illustrate conditioning the planarizing pad 140 toprovide a consistent pattern of grooves or other voids over the life ofthe pad. FIG. 3, more specifically, shows the planarizing pad 140 afterplanarizing one or more substrates 12, but before conditioning theplanarizing pad 140. During planarization, the substrate 12 can weardown the planarizing regions 146 to approximately the level of the topsurfaces 145 of the embedded regions 144, or waste matter W may glazeover certain regions of the planarizing pad 140. The waste matter W isespecially problematic in applications that planarize borophosphatesilicon glass (BPSG) or other relatively soft materials. In eithersituation, the planarizing surface of the planarizing pad 140 changes sothat the voids 147 in the base section 143 are either shallower orcompletely eliminated. The planarizing pad 140 must accordingly beconditioned to return the planarizing surface to a state that isacceptable for planarizing additional substrates 12.

[0028] To conditioning the planarizing pad 140, a selected conditioningsolution 160 is dispensed on the planarizing pad 140. The conditioningsolution 160 can be an etchant or another solution that dissolves orotherwise removes the second material of the embedded sections 144faster than the first material of the base section 143. The conditioningsolution 160 accordingly reforms the voids 147 over the embeddedsections 144 by incrementally removing a portion of the embeddedsections 144 each conditioning cycle. In a preferred embodiment, theplanarizing pad 140 is planarized to a level P-P before dispensing theconditioning solution 160 onto the planarizing pad 140 to remove thewaste matter W and to make the planarizing regions 146 coplanar with thetop surfaces 145 of the embedded sections 144. Referring to FIG. 4, theconditioning solution 160 then etches material from the embeddedsections 144 to incrementally lower the top surfaces 145 of the embeddedsections 144 below the surface of the planarizing regions 146. Eachconditioning cycle can thus incrementally lower the top surfaces 145 ofthe embedded sections 144 by pre-determined increments D₁, D₂, D₃, D₄,D₅ and so on.

[0029] One advantage of several embodiments of the planarizing pad 140illustrated in FIGS. 3 and 4 is that they provide a consistent patternof voids or grooves over the life of the planarizing pad. By arrangingthe embedded portions 144 in the desired pattern of voids, and byforming the embedded portions 144 to have a depth significantly greaterthan the depth of the voids 147, the second material of the embeddedsections 144 can be incrementally etched multiple times to consistentlyreform the voids 147. The reformed voids 147 can accordingly have thesame pattern, width and depth to provide a consistent distribution ofthe planarizing solution 139 under the substrate 12. Several embodimentsof the planarizing pad 140 are thus expected to provide more consistentplanarizing results than conventional planarizing pads because theygenerally eliminate one variable of the planarizing process thattypically changes over life of the planarizing pad (e.g., theconsistency of the voids).

[0030] Another advantage of several embodiments of the planarizing pad140 illustrated in FIGS. 3 and 4 is that these pads are expected to havelong operating lives. One aspect of certain embodiments of theplanarizing pad 140 is that the pad 140 can be conditioned several timeswithout changing the pattern or configuration of the voids 147. Theoperational life of the planarizing pad 140 is accordingly defined, atleast in part, by the depth of the embedded sections 144 in the basesection 143. The pad body 142 can thus be relatively thick so that theplanarizing pad 140 can be conditioned several times before it expires.Therefore, several embodiments of the polishing pad 140 illustrated inFIGS. 3 and 4 are expected to have long operating lives.

[0031]FIG. 5 is a schematic cross-sectional view of a stage in oneembodiment of a method for making the planarizing pad 140. In thisembodiment, the pad body 142 is a photo-sensitive compound that changeswhen it is exposed to light or other sources of radiation. Theradiation, for example, changes the exposed area of the photo-sensitivecompound to be more soluble in a selected chemical etchant. Suitablephoto-sensitive substances that become more soluble when exposed to UVlight include UV sensitive modified polyurethane. In one embodiment, theUV sensitive modified polyurethane has a photo-acid generator thatterminates the polyurethane groups with phenol groups, and then thecompound is subject to esterification. The photo-acid generator, forexample, can be sulfonium salt. Upon irradiation, the photo-acidgenerator breaks apart and releases an acid that forms groups that aresoluble in a solution (e.g., ester groups that are soluble in a base).The etchant can accordingly be in the hydroxide group, such as ammoniumhydroxide (NH₃OH).

[0032] The method continues by placing a mask 170 on the top surface ofthe pad body 142. The mask 170 has an opaque section 171 and a pluralityof transmissive sections 172 (e.g., apertures). The transmissivesections 172 are arranged in the pattern of the voids 147 for theplanarizing pad 140. After the mask 170 is positioned over the pad body142, a radiation source 174 irradiates the exposed areas of the pad body142 under the transmissive sections 172 with a selected radiation tochange the property of the exposed areas of the photo-sensitivematerial. The particular radiation from the radiation source 174 isselected according to the photo properties of the photo-sensitivesubstance of the pad body or 142. Additionally, the intensity of theselected radiation and the time of exposure is selected to control thedepth D of the material changed by the irradiation.

[0033] The exposed areas of the pad body 142 in this embodimentaccordingly define the embedded sections 144, and the non-exposed areasof the pad body 144 define the base section 143. Suitable procedures forforming the embedded sections 144 include illuminating a pad body 142 ofUV sensitive modified material with UV radiation at approximately 300nm. After exposing the pad body 142 to the selected radiation, anetchant or another type of selected solution is disposed on theplanarizing pad 140 to remove the second material of the embeddedsections 144 faster than the first material of the base section 143. Theresulting planarizing pad 140 accordingly has a plurality of voids 147over the embedded sections 144 (as shown in FIG. 4).

[0034] In an alternate embodiment of the process illustrated in FIG. 5,the photo-sensitive substance of the pad body 142 can be changed inplanarizing regions 146 to be less soluble in a selected solution. Inthis embodiment, the transmissive sections in the mask are positionedover the desired areas of the planarizing regions 146 and the opaquesections are patterned to correspond to the pattern of the embeddedsections 144 described above with reference to FIG. 5. As describedabove with reference to FIG. 5, an etchant or other selected solution isdisposed on the planarizing pad 140 to selectively etch the secondmaterial of the embedded sections 144 faster than the first material ofthe base section 143.

[0035]FIG. 6 is a schematic cross-sectional view of a stage in anotherembodiment of a method for making the planarizing pad 140. In thisembodiment, the pad body 142 is composed of a photo-sensitive material,and the method includes irradiating either the embedded sections 144 orthe planarizing sections 146 of the pad body 142 with a highlydirectional beam 273 from a laser 274 or other radiation source. Thisembodiment for making the polishing had 140 accordingly changes thephoto-sensitive material so that the base section 143 is composed of thefirst material and the embedded sections 144 are composed of the secondmaterial. After irradiating the pad body 142 with the laser 274, anetchant or another type of solution is disposed on the planarizing pad140 to selectively etch the voids.

[0036] FIGS. 7A-7D illustrate another method for manufacturing theplanarizing pad 140 in accordance with another embodiment of theinvention. Referring to FIG. 7A, a plurality of deep depressions 141 areinitially formed in the pad body 142 to define the planarizing regions146 of the base section 143. The deep depressions 141 generally have adepth corresponding to the depth of the embedded sections 144 (FIG. 5),and the depressions 141 are arranged in the desired pattern of voids forthe planarizing pad 140. The deep depressions 141 can be formed bystamping or etching the pad body 142. Referring to FIG. 7B, a coverlayer 149 is then formed over the base section 143 to fill thedepressions 141. Referring to FIG. 7C, the pad body 142 is thenplanarized to remove the upper portion of the cover layer 149 so thatthe remaining portions of the cover layer 149 are isolated from oneanother in the depressions 141. The original material of the pad body142 in which the depressions 141 were formed constitutes the basesection 143, and the remaining portions of the cover layer 149 in thedepressions 141 after planarizing the pad constitute the embeddedsections 144.

[0037] In the embodiment of the planarizing pad 140 shown in FIGS.7A-7C, the first material of the base section 143 and the secondmaterial of the embedded sections 144 can be different compounds orsubstances. The first material, for example, can include polyurethane,resin, polyester or other materials. The first material can be amaterial that is not readily attacked by a strong oxidizer. The secondmaterial can include nylon, polycarbonate, polystyrene, butadieneacrylonitrile or other materials. The second material can be a materialthat is readily attacked by a strong oxidizer. The first and secondmaterials are selected so that the second material is selectivelyremovable from the first material by a selected etchant or othersolution. The etchant, for example, can be a strong oxidizer, such asperoxide or ozonated water. Referring to FIG. 7D, an etchant or selectedsolution is disposed on the planarized planarizing pad 140 shown in FIG.7C to etch the voids 147 above the embedded sections 144.

[0038] FIGS. 8A-8E illustrate a method for photo-patterning and etchingthe deep depressions 141 in the pad body 142. As shown in FIG. 8A, aphotopolymer composite 350 is formed by disposing a photopolymer resistmaterial 353 on a substrate polymer 351. The photopolymer resistmaterial 353 is then exposed to a radiation source 364. A mask 280 hasopaque portions 281 to block the radiation emitted from the radiationsource 364 from striking unexposed portions 355 of the photopolymerresist material 353, and the mask 280 has transmissive portions 282through which the radiation passes to strike exposed portions 354 of theresist material 353.

[0039] As shown schematically in FIG. 8B, the radiation source 263changes chemical characteristics of the exposed portions 354. Forexample, when the photopolymer resist material 353 is initiallyinsoluble in a selected solvent, exposure to the selected radiation canchange the exposed portions 354 to become soluble in the selectedsolvent. Alternatively, when the photopolymer resist material isinitially soluble in the selected solvent, exposure to the selectedradiation can make the exposed portions 354 insoluble. In either case,the solubility of the unexposed portions 355 remains unchanged.

[0040] When the exposed portions 354 are rendered insoluble by exposureto the selected radiation, FIG. 8C schematically illustrates thephotopolymer composite 350 after being rinsed with the selected solvent.The exposed portions 354 of the photopolymer resist material 353 remainintact and the unexposed portions 355 (FIG. 8B) have been removed by thesolvent to expose the substrate polymer 352 below. The substrate polymer352 is then etched to remove the portions of the substrate polymermaterial between the exposed portions 354 and form the deep depressions141 (FIG. 8D). The exposed portions 354 of the photopolymer resistmaterial 353 are then removed to form the pad body 142 with the deepdepressions 141. The pad body 142 shown in FIG. 8D is then processed asexplained above with reference to FIGS. 7B-7D.

[0041]FIG. 9 is a schematic cross-sectional view of another procedurefor forming the depressions 141 in the first material of the pad body142. In this embodiment, a press 480 is driven against the pad body 142while the pad body 142 is in a deformable state. The pad body 142, forexample, can be heated or formed from a flowable material that can behardened using heat and/or chemical curing processes. The press 480includes a plate 481 having a plurality of projections 482 and recesses489 between the projections 482. The projections 482 accordingly formthe deep depressions 141, and the recesses 489 form the planarizingregions 146. The stamped pad body 142 is then cooled or otherwise curedto harden the pad body 142 to a useable state. The hardened pad body 142can then be processed as explained above with reference to FIGS. 7B-7D.

[0042] From the foregoing it will be appreciated that even thoughspecific embodiments of the invention have been described herein forpurposes of illustration, various modifications may be made withoutdeviating from the spirit and scope of the invention. For example, theplanarizing pad 140 can also be a web-format pad for use on a web-formatplanarizing machine. Accordingly, the invention is not limited except asby the appended claims.

1. In the manufacturing of microelectronic devices, a method of making aplanarizing pad comprising: forming a pad body by constructing a basesection and embedded sections in the base section, the base sectionbeing composed of a first material and the embedded sections beingcomposed of a second material selectively removable from the firstmaterial, and the embedded sections being arranged in a patterncorresponding to a desired pattern of voids in the base section forholding a planarizing solution during a planarizing cycle; and removinga portion of the second material from the first material withoutremoving all of the second material to create a plurality of voids inthe base section over remaining portions of the second material in theembedded sections.
 2. The method of claim 1 wherein: the pad bodyinitially comprises a photosensitive material that becomes more solublein a selected etchant upon exposure to a selected radiation, thephotosensitive material defining the first material; and constructingthe base section and the embedded sections in the base section comprisesirradiating the first material with the selected radiation in thedesired pattern of voids to change the irradiated portions of the firstmaterial into the second material, the depth of the second materialbeing greater than a desired depth of the voids.
 3. The method of claim1 wherein: the pad body initially comprises a photosensitive materialthat becomes less soluble in a selected etchant upon exposure to aselected radiation, the photosensitive material defining the secondmaterial; and constructing the base section and the embedded sections inthe base section comprises irradiating the second material with theselected radiation in a pattern of contact sections of the base sectionto change the irradiated portions into the first material of the basesection and to leave un-irradiated sections of the second material inthe desired pattern of voids.
 4. The method of claim 1 wherein: the padbody initially comprises a photosensitive material that becomes moresoluble in a selected etchant upon exposure to a selected radiation, thephotosensitive material defining the first material; and constructingthe embedded sections in the base section comprises illuminating thefirst material with the selected radiation by moving a laser across thefirst material in the desired pattern of voids to change the illuminatedportions of the first material into the second material, the depth ofthe second material being greater than a desired depth of the voids. 5.The method of claim 1 wherein: the pad body initially comprises aphotosensitive material that becomes more soluble in a selected etchantupon exposure to a selected radiation, the photosensitive materialdefining the first material; and constructing the embedded sections inthe base section comprises illuminating the first material with theselected radiation by photo-patterning the first material with theselected radiation in the desired pattern of voids to change theirradiated portions of the first material into the second material, thedepth of the second material being greater than a desired depth of thevoids.
 6. The method of claim 1 wherein: constructing the embeddedsections in the base section comprises providing a sheet of the firstmaterial and forming deep depressions in the first material in thedesired pattern of voids, depositing the second material onto the firstmaterial to fill the deep depressions with the second material and tocover the first material, and planarizing the second material to exposea top surface of the first material between the second material in thedepressions; and removing a portion of the second material comprisesselectively etching an incremental portion of the second material fromthe first material with a selective etchant that removes the secondmaterial faster than the first material.
 7. The method of claim 1wherein: the first material comprises; constructing the embeddedsections in the base section comprises providing a sheet of polyurethaneand forming deep depressions in the first material in the desiredpattern of voids, depositing the second material onto the first materialto fill the deep depressions with the second material and to cover thefirst material, and planarizing the second material to expose a topsurface of the first material between the second material in thedepressions, the second material comprising nylon; and removing aportion of the second material comprises selectively etching the secondmaterial from the first material with a selective etchant that removesthe second material faster than the first material.
 8. The method ofclaim 1 wherein: the first material comprises polyurethane; constructingthe embedded sections in the first material comprises providing a sheetof the first material and forming deep depressions in the first materialin the desired pattern of voids, separately depositing the secondmaterial onto the first material to fill the deep depressions with thesecond material and to cover the first material, and planarizing thesecond material to expose a top surface of the first material betweenthe second material in the depressions, the second material comprisingpolycarbonate; and removing a portion of the second material comprisesselectively etching the second material from the first material with aselective etchant that removes an incremental portion of the secondmaterial faster than the first material.
 9. The method of claim 1wherein: the first material comprises polyurethane; constructing theembedded sections in the first material comprises providing a sheet ofthe first material and forming deep depressions in the first material inthe desired pattern of voids, separately depositing the second materialonto the first material to fill the deep depressions with the secondmaterial and to cover the first material, and planarizing the secondmaterial to expose a top surface of the first material between thesecond material in the depressions, the second material comprisingpolystyrene; and removing a portion of the second material comprisesselectively etching the second material from the first material with aselective etchant that removes an incremental portion of the secondmaterial faster than the first material.
 10. The method of claim 1wherein: the first material comprises polyurethane; constructing theembedded sections in the first material comprises providing a sheet ofthe first material and forming deep depressions in the first material inthe desired pattern of voids, separately depositing the second materialonto the first material to fill the deep depressions with the secondmaterial and to cover the first material, and planarizing the secondmaterial to expose a top surface of the first material between thesecond material in the depressions, the second material comprisingbutadiene acrylonitrile; and removing a portion of the second materialcomprises selectively etching the second material from the firstmaterial with a selective etchant that removes an incremental portion ofthe second material faster than the first material.
 11. In themanufacturing of microelectronic devices, a method of making aplanarizing pad comprising: providing a pad body composed of a firstmaterial; changing a property of selected sections of the first materialin a desired pattern of voids to form a pattern of a second material inthe first material, the second material being selectively removable fromthe first material; and selectively removing a portion of the secondmaterial from the first material to an intermediate depth within thesecond material to form a plurality of voids in the void pattern and toleave a remaining portion of the second material under the voids. 12.The method of claim 11 wherein: the first material of the pad bodycomprises a photosensitive material that defines the first material ofthe base section and becomes more soluble in a selected etchant uponexposure to a selected radiation; and changing a property of selectedportions of the first material comprises irradiating the first materialwith the selected radiation in the desired pattern of voids to changethe irradiated portions of the first material into the second material.13. The method of claim 11 wherein: the first material of the pad bodycomprises a photosensitive material that defines the first material ofthe base section and becomes more soluble in a selected etchant uponexposure to a selected radiation; and changing a property of selectedportions of the first material comprises irradiating the first materialwith the selected radiation in the desired pattern of voids by moving alaser across the base section in the desired pattern of voids to changethe irradiated portions of the first material into the second material.14. The method of claim 11 wherein: the first material of the pad bodycomprises a photosensitive material that defines the first material ofthe base section and becomes more soluble in a selected etchant uponexposure to a selected radiation; and changing a property of selectedportions of the first material comprises irradiating the first materialwith the selected radiation in the desired pattern of voids byphoto-patterning the first material with the selected radiation in thedesired pattern of voids to change the irradiated portions of the firstmaterial into the second material.
 15. In the manufacturing ofmicroelectronic devices, a method of making a planarizing padcomprising: providing a pad body composed of a first material; forming aplurality of deep depressions in the first material in a desired patternof embedded sections; filling the depressions with a second materialthat is selectively removable from the first material to form theembedded sections; and selectively removing a portion of the secondmaterial from the first material to an intermediate depth within thesecond material to form a plurality of voids in the void pattern and toleave a remaining portion of the second material under the voids. 16.The method of claim 15 wherein: forming the plurality of deepdepressions comprises etching the deep depressions in the pad body; andselectively removing the second material from the first materialcomprises etching only a portion of the second material.
 17. The methodof claim 15 wherein: forming the plurality of deep depressions comprisesstamping the deep depressions in the pad body; and selectively removingthe second material from the first material comprises etching only aportion of the second material.
 18. The method of claim 15 wherein:providing a pad body composed of a first material comprises fabricatinga sheet of polyurethane; forming the plurality of deep depressionscomprises etching the deep depressions in the pad body; filling thedepressions comprises depositing a second material comprisingpolycarbonate, polystyrene and/or nylon on the first material; andselectively removing the second material from the first materialcomprises etching only a portion of the second material.
 19. The methodof claim 15 wherein: providing a pad body composed of a first materialcomprises fabricating a sheet of polyurethane; forming the plurality ofdeep depressions comprises etching the deep depressions in the pad body;filling the depressions comprises depositing a second materialcomprising butadiene acrylonitrile on the first material; andselectively removing the second material from the first materialcomprises planarizing the second material to expose a top surface of thefirst material and then etching only a portion of the second material.20. A method of planarizing a microelectronic device substrate assembly,comprising: providing a planarizing pad having a base section having aplanarizing surface of a first material, a plurality of embeddedsections of a second material in the first material, and a plurality ofvoids in the first material above the embedded sections, the voidsextending below the planarizing surface, and the second material beingselectively removable from the first material by a selected solution;pressing the microelectronic device substrate assembly against theplanarizing surface in the presence of a planarizing solution on theplanarizing pad and in the voids; and moving at least one of theplanarizing pad and/or the microelectronic device substrate assemblyrelative to one another.
 21. The method of claim 20, further comprisingconditioning the planarizing pad between planarizing cycles byselectively removing the second material in the embedded sections fasterthan the first material -of the base section to reform voids in basesection over the embedded sections.
 22. The method of claim 20, furthercomprising conditioning the planarizing pad between planarizing cyclesby depositing the selected solution onto the planarizing pad toselectively remove the second material in the embedded sections fasterthan the first material of the base section.
 23. The method of claim 20,further comprising conditioning the polishing pad between planarizingcycles by: removing an incremental layer of the pad body to form asurface in which the base section has an upper surface and the embeddedsections have top surfaces generally co-planar with the upper surface ofthe base section; and selectively etching an additional incrementalportion of the second material in the embedded sections faster than theupper surface of the base section to reform voids in the base sectionover the embedded sections.
 24. The method of claim 20, furthercomprising conditioning the polishing pad between planarizing cycles by:removing an incremental layer of the pad body to form a surface in whichthe base section has an upper surface and the embedded sections have topsurfaces generally co-planar with the upper surface of the base section;and depositing a chemical solution on the bad body to remove anadditional incremental portion of the second material in the embeddedsections faster than the upper surface of the base section to reformvoids in the base section over the embedded sections.
 25. A method ofplanarizing a microelectronic device substrate assembly, comprising:disposing a planarizing solution onto a planarizing surface of aplanarizing pad to at least partially fill voids over embedded sectionsof the pad, the embedded sections being arranged in a desired pattern ofvoids in a first material, wherein the base section is composed of afirst material and the embedded sections are composed of a secondmaterial that is selectively removable from the first material by aselected solution; and removing material from the substrate assembly bypressing the microelectronic device substrate assembly against theplanarizing pad and moving at least one of the planarizing pad and/orthe microelectronic device substrate assembly relative to the other. 26.The method of claim 20, further comprising conditioning the planarizingpad between planarizing cycles by selectively removing the secondmaterial in the embedded sections faster than the first material of thebase section to reform voids in base section over the embedded sections.27. The method of claim 20, further comprising conditioning theplanarizing pad between planarizing cycles by depositing the selectedsolution onto the planarizing pad to selectively remove the secondmaterial in the embedded sections faster than the first material of thebase section.
 28. The method of claim 25, further comprisingconditioning the polishing pad between planarizing cycles by: removingan incremental layer of the pad body to form a surface in which the basesection has an upper surface and the embedded sections have top surfacesgenerally co-planar with the upper surface of the base section; andselectively etching an additional incremental portion of the secondmaterial in the embedded sections faster than the upper surface of thebase section to reform voids in the base section over the embeddedsections.
 29. The method of claim 25, further comprising conditioningthe polishing pad between planarizing cycles by: removing an incrementallayer of the pad body to form a surface in which the base section has anupper surface and the embedded sections have top surfaces generallyco-planar with the upper surface of the base section; and depositing achemical solution on the bad body to remove an additional incrementalportion of the second material in the embedded sections faster than theupper surface of the base section to reform voids in the base sectionover the embedded sections.
 30. A planarizing pad for mechanical orchemical-mechanical planarization of microelectronic device substrateassemblies, comprising: a base section having a planarizing surface, thebase section being composed of a first material; and a plurality ofembedded sections in the base section, the embedded sections beingarranged in a desired void pattern and each embedded section having atop surface below the planarizing surface to define a plurality of voidsin the base section, and the embedded sections being composed of asecond material that is selectively removable from the first material.31. The planarizing pad of claim 30 wherein: the first materialcomprises a first photosensitive compound; and the second materialcomprises a second compound formed by exposing the first photosensitivecompound to a radiation source that chemically changes the firstphotosensitive compound to the second compound.
 32. The planarizing padof claim 30 wherein: the second material comprises a photosensitivecompound having a first solubility in an etchant; the first materialcomprises a resistant compound formed by exposing the photosensitivecompound to a radiation source that chemically changes thephotosensitive compound to the resistant compound, the resistantcompound having a second solubility in the etchant less than the firstsolubility.
 33. The planarizing pad of claim 30 wherein: the firstmaterial comprises polyurethane; and the second material comprisespolycarbonate, polystyrene and/or nylon.
 34. The planarizing pad ofclaim 30 wherein: the first material comprises polyurethane; and thesecond material comprises butadiene acrylonitrile.
 35. A planarizing padfor mechanical or chemical-mechanical planarization of microelectronicdevice substrate assemblies, comprising: a base section of a firstmaterial, the base section having a planarizing surface; a plurality ofembedded sections in the base section, the embedded sections being asecond material selectively removable from the first material by aselected solution; and a plurality of voids over the embedded sectionsto form cavities in the base section extending below the planarizingsurface.
 36. The planarizing pad of claim 35 wherein: the first materialcomprises a first photosensitive compound; and the second materialcomprises a second compound formed by exposing the first photosensitivecompound to a radiation source that chemically changes the firstphotosensitive compound to the second compound.
 37. The planarizing padof claim 35 wherein: the second material comprises a photosensitivecompound having a first solubility in the selected solution; and thefirst material comprises a resistant compound formed by exposing thephotosensitive compound to a radiation source that chemically changesthe photosensitive compound to the resistant compound, the resistantcompound having a second solubility in the selected solution less thanthe first solubility.
 38. The planarizing pad of claim 35 wherein: thefirst material comprises polyurethane; and the second material comprisespolycarbonate, polystyrene and/or nylon.
 39. The planarizing pad ofclaim 35 wherein: the first material comprises polyurethane; and thesecond material comprises butadiene acrylonitrile.
 40. A planarizingmachine for mechanical or chemical-mechanical planarization ofmicroelectronic device substrate assemblies, comprising: a table; aplanarizing pad on the table, the pad including a base section and aplurality of embedded sections in the base section, the base sectionhaving a planarizing surface and the base section being composed of afirst material, the plurality of embedded sections being arranged in adesired void pattern and each embedded section having a top surfacebelow the planarizing surface to define a plurality of voids in the basesection, and the embedded sections being composed of a second materialthat is selectively removable from the first material; and a carrierassembly having a carrier head configured to hold a microelectronicdevice substrate assembly, the carrier head being movable to press thesubstrate assembly against the planarizing surface during a planarizingcycle.
 41. The planarizing machine of claim 40 wherein: the firstmaterial comprises a first photosensitive compound; and the secondmaterial comprises a second compound formed by exposing the firstphotosensitive compound to a radiation source that chemically changesthe first photosensitive compound to the second compound.
 42. Theplanarizing machine of claim 40 wherein: the second material comprises aphotosensitive compound having a first solubility in an etchant; and thefirst material comprises a resistant compound formed by exposing thephotosensitive compound to a radiation source that chemically changesthe photosensitive compound to the resistant compound, the resistantcompound having a second solubility in the etchant less than the firstsolubility.
 43. The planarizing machine of claim 40 wherein: the firstmaterial comprises polyurethane; and the second material comprisespolycarbonate, polystyrene and/or nylon.
 44. The planarizing machine ofclaim 40 wherein: the first material comprises polyurethane; and thesecond material comprises butadiene acrylonitrile.
 45. A planarizingmachine for mechanical or chemical-mechanical planarization ofmicroelectronic device substrate assemblies, comprising: a table; aplanarizing pad on the table, the planarizing pad having a base sectionof a first material, a plurality of embedded sections of a secondmaterial in the base section, and a plurality of voids in the basesection over the embedded sections, the base section having aplanarizing surface and the voids extending through the base sectionbelow the planarizing surface to the embedded sections, and the secondmaterial being selectively removable from the first material by aselected solution; and a carrier assembly having a carrier headconfigured to hold a microelectronic device substrate assembly, thecarrier head being movable to press the substrate assembly against theplanarizing surface during a planarizing cycle.
 46. The planarizingmachine of claim 40 wherein: the first material comprises a firstphotosensitive compound; and the second material comprises a secondcompound formed by exposing the first photosensitive compound to aradiation source that chemically changes the first photosensitivecompound to the second compound.
 47. The planarizing machine of claim 40wherein: the second material comprises a photosensitive compound havinga first solubility in the selected solution; and the first materialcomprises a resistant compound formed by exposing the photosensitivecompound to a radiation source that chemically changes thephotosensitive compound to the resistant compound, the resistantcompound having a second solubility less than the first solubility. 48.The planarizing machine of claim 40 wherein: the first materialcomprises polyurethane; and the second material comprises polycarbonate,polystyrene and/or nylon.
 49. The planarizing machine of claim 40wherein: the first material comprises polyurethane; and the secondmaterial comprises butadiene acrylonitrile.